(1) Field of the Invention
The present invention relates to an electric junction box to be mounted on a motor vehicle and so on as a mobile unit.
(2) Description of the Related Art
A motor vehicle as a mobile unit is generally equipped with various electronic equipment, that is, lamps such as a head lamp and tail lamp, and motors such as a starter motor and motor for an air-conditioner.
In order to supply electric power to the various electronic equipment, a junction block has been arranged at a suitable position in the motor vehicle. The junction block is composed of various electric circuit units such as many fuses and relays.
In this connection, since the junction block may include fuses, relays, busbars and so on, therefore it may be called a fuse block, relay box or electric junction box as a generic term. In this specification, such a fuse block, relay box or junction block is called an electric junction box as a generic term.
An electric junction box includes a box body, which forms an external form, an electric block to be attached to the box body, and so on. The box body is formed in a box-shape. The electric block includes: an electric component to be attached to the box body such as a fuse and relay; and a terminal fitting attached to an end of an electric wire.
The terminal fitting is attached to the box body so as to be connected electrically and mechanically to a terminal of an electric component attached to the box body. The terminal fitting electrically connects the electric wire to the electric component. The electric wire attached to the terminal fitting is connected to the electric component. The electric junction box having a construction described above electrically connects the electric wire attaching the terminal fitting to the electric component such as a relay and fuse in accordance with a predetermined pattern.
The terminal fitting attached to the electric wire and the electric component such as a fuse and relay are attached to the box body one by one, so that the electric junction box is assembled. Therefore, a time and man-hour required to assemble the junction box tend to increase.
In order to solve the above problem, proposed is an electric junction box, in which the box body is formed in a frame-shape so as to provide a cassette block detachable to the box body, and the terminal fitting, relay and fuse are mounted in the cassette block (for example, see Japanese Patent Application Laid-Open No. 2004-312793 and Japanese Patent Application Laid-Open No. 2000-23331). In the electric junction box disclosed in these Patent Publication, the box body is provided with a frame-shaped body part and a partition wall for partitioning the inside of the body part into a plurality of spaces, and the terminal fitting and the electric component such as relay and fuse are mounted in the cassette block, and the cassette block is received in between the partition walls so as to attached to the box body, so that the terminal fitting and the electric component such as relay and fuse can be collectively mounted in the box body. As a result, the electric junction box disclosed in these Patent Publication restricts a time and man-hour required to assemble the junction box.
The cassette block is received in between the partition walls adjacent to each other in the box body of the electric junction box disclosed in the above Patent Publication. The box body is made of electrically insulating synthetic resin and molded by known injection molding.
Therefore, as for the box body described above, when the number of electric components increases or a size of the electric component increases, a distance between the partition walls is increased, causing deterioration in stiffness of the box body. Therefore, when the cassette block is inserted into between the partition walls, the box body tends to be deformed, resulting in that the cassette block is hardly inserted into between the partition walls.
Moreover, since the box body described above is made of synthetic resin and molded by known injection molding, the box body tends to be deformed upon injection molding or when the molded product is taken out from a mold, since the body part of the box body is formed in a frame-shape. In this case as well, of course, the cassette block is hardly inserted into between the partition walls.